Research on the setting of maximum pressure in salt caverns intended for CO₂ storage

The caverns are built in the salt massifs, by dissolving the salt at depths from 150 m to 1000÷2000m, and can have a volume between 5000 and 1 000 000 m3. These can provide the storage of large amounts of hydrocarbons, hydrogen or carbon dioxide. Sealing is a fundamental prerequisite for many underground works where it is necessary for the stored product to have minimal leakage. The main factors in the appearance of well leakage are: Fluid pressure distribution, geological environment, well cementing operation and cavern architecture. For a functioning cavern, fracturing the walls is a major risk, which can lead to loss of tightness. Consequently, the pressure of the stored product must be less than the absolute value of the lowest compression effort, even when a margin of safety is being taken. Knowledge of these efforts, their evolution over time and their distribution around the caverns, is the research objective for the authors of this article. For real-scale analysis, a 3D model of finite element analysis was used, using numerical modelling software for geotechnical analysis of rocks.